A wide variety of different types of cables are utilized to transmit signals. For example, communication cables, such as twisted pair and optical fiber cables, are utilized to transmit data signals. Plenum cables include cables designed for use in horizontal or plenum spaces within a facility, such as spaces utilized for heating and air conditioning systems. Applicable cable and fire standards, such as the National Fire Protection Act (“NFPA”) standard 90A, require plenum cables to satisfy rigorous fire safety tests. As a result, plenum cables are typically constructed to include materials that increase flame resistance, reduce smoke generation, and/or limit flame spread.
Depending on the design of a cable, a wide variety of different components may be included, such as insulation layers, separators, buffer tubes, tapes or wraps, and/or cable jackets. Each components of the cable can affect the flame performance of the overall cable. Conventional cables typically include components that are formed from relatively expensive materials, such as fluorinated ethylene propylene (“FEP”). In higher pair count cables, it is often necessary to utilize even more expensive jacket materials, such as FEP or polyvinylidene fluoride (“PVDF”) jacket materials. However, the high cost of these materials makes their use less desirable, and a wide variety of attempts have been made to reduce the amount of these materials incorporated into cables while still satisfying desired electrical performance criteria.
The use of lower cost insulation materials, such as polypropylene (“PP”), high-density polyethylene (“HDPE”), and medium-density polyethylene (“MDPE”), typically results in greater flame spread and higher smoke generation when subjected to plenum burn test. As a result, it is often not desirable to use these materials in plenum cables. However, there is an opportunity for flame retardant insulation materials that can be utilized to form components within plenum cables. There is also an opportunity for improved insulation materials that are less expensive than conventional flame retardant materials, such as solid FEP or PVDF.